Open Problems


TitleAuthor(s)Imp.¹sort iconRec.²Area » Topic » SubtopicPosted by
What is the largest graph of positive curvature?DeVos; Mohar1Graph Theory » Topological G.T. » Planar graphsmdevos
End-Devouring RaysGeorgakopoulos1Graph Theory » Infinite GraphsAgelos
Combinatorial covering designsGordon; Mills; Rödl; Schönheim0Combinatorics » DesignsPseudonym
Termination of the sixth Goodstein SequenceGraham0Logicmdevos
Criterion for boundedness of power seriesRüdinger1Analysisandreasruedinger
Are there an infinite number of lucky primes?Lazarus: Gardiner: Metropolis; Ulam1Number Theory » Additive N.T.cubola zaruka
Point sets with no empty pentagonWood1GeometryDavid Wood
Special PrimesGeorge BALAN1Number Theorymaththebalans
Covering powers of cycles with equivalence subgraphs0Graph TheoryAndrew King
Strict inequalities for products of filtersPorton0Topologyporton
Obstacle number of planar graphsAlpert; Koch; Laison1Graph TheoryAndrew King
Length of surreal productGonshor1CombinatoricsLukáš Lánský
Circular choosability of planar graphsMohar0Graph Theory » Coloring » Homomorphismsrosskang
Mixing Circular ColouringsBrewster; Noel1Graph Theory » Coloring » Vertex coloringJon Noel
Melnikov's valency-variety problemMelnikov0Graph Theory » Coloring » Vertex coloringasp
Weak saturation of the cube in the cliqueMorrison; Noel1Graph Theory » Extremal G.T.Jon Noel
The three 4-flows conjectureDeVos✭✭0Graph Theory » Coloring » Nowhere-zero flowsmdevos
A homomorphism problem for flowsDeVos✭✭0Graph Theory » Coloring » Nowhere-zero flowsmdevos
Real roots of the flow polynomialWelsh✭✭0Graph Theory » Coloring » Nowhere-zero flowsmdevos
Unit vector flowsJain✭✭0Graph Theory » Coloring » Nowhere-zero flowsmdevos
Packing T-joinsDeVos✭✭0Graph Theory » Coloring » Edge coloringmdevos
Acyclic edge-colouringFiamcik✭✭0Graph Theory » Coloring » Edge coloringmdevos
Partitioning edge-connectivityDeVos✭✭0Graph Theory » Basic G.T. » Connectivitymdevos
The permanent conjectureKahn✭✭0Combinatorics » Matricesmdevos
The Alon-Tarsi basis conjectureAlon; Linial; Meshulam✭✭0Combinatorics » Matricesmdevos
Olson's ConjectureOlson✭✭0Number Theory » Combinatorial N.T.mdevos
Few subsequence sums in Z_n x Z_nBollobas; Leader✭✭0Number Theory » Combinatorial N.T.mdevos
The stubborn list partition problemCameron; Eschen; Hoang; Sritharan✭✭0Graph Theory » Graph Algorithmsmdevos
Graham's conjecture on tree reconstructionGraham✭✭0Graph Theory » Basic G.T.mdevos
The Two Color ConjectureNeumann-Lara✭✭0Graph Theory » Directed Graphsmdevos
A generalization of Vizing's Theorem?Rosenfeld✭✭0Graph Theory » Coloring » Edge coloringmdevos
The Crossing Number of the HypercubeErdos; Guy✭✭0Graph Theory » Topological G.T. » Crossing numbersRobert Samal
Drawing disconnected graphs on surfacesDeVos; Mohar; Samal✭✭0Graph Theory » Topological G.T. » Crossing numbersmdevos
Antichains in the cycle continuous orderDeVos✭✭0Graph Theory » Coloring » Nowhere-zero flowsmdevos
Gao's theorem for nonabelian groupsDeVos✭✭0Number Theory » Combinatorial N.T.mdevos
Half-integral flow polynomial valuesMohar✭✭0Graph Theory » Algebraic G.T.mohar
A conjecture on iterated circumcentresGoddyn✭✭1Geometrymdevos
List colorings of edge-critical graphsMohar✭✭0Graph Theory » Coloring » Edge coloringRobert Samal
Circular coloring triangle-free subcubic planar graphsGhebleh; Zhu✭✭0Graph Theory » Coloring » Vertex coloringmdevos
Concavity of van der Waerden numbersLandman✭✭0Combinatorics » Ramsey TheoryBruce Landman
Laplacian Degrees of a GraphGuo✭✭0Graph Theory » Algebraic G.T.Robert Samal
5-local-tensionsDeVos✭✭0Graph Theory » Topological G.T. » Coloringmdevos
Long rainbow arithmetic progressionsFox; Jungic; Mahdian; Nesetril; Radoicic✭✭0Combinatoricsvjungic
Weak pentagon problemSamal✭✭0Graph Theory » Coloring » HomomorphismsRobert Samal
Complexity of square-root sumGoemans✭✭0Theoretical Comp. Sci. » Complexityabie
Linear-size circuits for stable $0,1 < 2$ sorting?Regan✭✭1Theoretical Comp. Sci. » ComplexityKWRegan
Rainbow AP(4) in an almost equinumerous coloringConlon✭✭0Combinatoricsvjungic
Infinite uniquely hamiltonian graphsMohar✭✭0Graph Theory » Infinite GraphsRobert Samal
Hamiltonian cycles in line graphs of infinite graphsGeorgakopoulos✭✭0Graph Theory » Infinite GraphsRobert Samal
Hamiltonian cycles in powers of infinite graphsGeorgakopoulos✭✭0Graph Theory » Infinite GraphsRobert Samal
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